ABEYANCE SEAL FOR HIGH TEMPERATURE, HIGH PRESSURE APPLICATIONS

摘要

An abeyance seal (10) is provided to prevent leakage to environment past a primary mechanical sea. The abeyance seal includes a polymer actuation ring (12), which is the first line of sealing actuation and defines a flexible sealing lip (14) normally spaced from the shaft. When subjected to leakage, this element collapses against the shaft or shaft sleeve (15) and forms an initial sealing. Actuation of this element occurs at lower leakage flows due to high velocity steam, two phase flow, or gas. Secondarily, a metal sealing/anti-extrusion ring (18) is provided. Increased sealed pressure loads the polymer ring against the metal sealing/anti-extrusion ring causing it to deform so that the inside diameter of the metal ring comes into contact with the shaft or shaft sleeve to form a second seal. Seal actuation is not dependent on temperature but on actual leakage flow.